Hi The Engineer,
With regard the two Douglas engines I can confirm the OHV engine is of the type deveoped during WW2 and used to power a 1200VA/350 Watt Generating Set. It is of 350cc capacity and formed the basis of the first post war Douglas production motorcycle the T35.
The second engine was used to power a Douglas Industrial Truck. The engine number and letter prefix which although looking like FFT should probably read just FT. The actual number of 5094 would denote a power unit from the Series 10 models of trucks. There were 5 models in the series namely:-
Low Loading Non-elavating
" " Elavating Platform
High Loading Non-Elavating
" " Elavating Platform
The High Lift
I have no information regarding year of manufacture.
The engine is of 600cc having side by side valves mounted in the cylinder barrels which have detachable light alloy cylinder heads.
The crankshaft speed was governed to 2,800rpm. The steering of these trucks provided by large diameter wheel, operated from the drivers seat, via reduction gear to front wheel which is vertically revolved through a circle of 360 degrees, providing both forward and reverse drive. The truck's speed was governed to 7 mph. I would suggest any spare parts for the earlier engines would have to be accessed through Stationary Engine clubs. Hope this is of some help.
Reg